There are four levels of nitrogen, corresponding to treatments A, C, E and G in CDR001, applied at the same time as in that experiment. There are four levels of soil disturbance:

level 1: undisturbed

level 2: one pass with a 7 HP ... Honda rear-tined rototiller with the elevator set at the second notch (from the top)

level 3: two passes or however many required to produce about 50% bare ground

level 4: three passes or however many required to produce 100% bare ground.

This requires three passes in some plots but five or six in others. In addition, all woody vegetation not destroyed by tilling is cut at the base. Rototilling is applied in late April. Each fertilization treatment receives each disturbance treatment, for a total of sixteen treatments. There are four replicates of each of the sixteen treatments. In addition, the four extreme ends (lowest N, lowest disturbance; highest N, lowest disturbance, etc.) are replicated an additional ten times. Treatments are applied in a completely randomized design. Each of the 104 plots is 5 m x 5 m. Measurements taken at CDR017 will include: 1) species abundances, 2) community biomass allocation to leaves/roots/stems/flowers, 3) aboveground and belowground NPP, and 4) rates of nitrogen mineralization.

Proprietary limits: Investigators have priority over data for five years, but are interested in collaboration for novel comparisons before then.

The Cedar Creek Natural History Area (CCNHA) is a 2200 hectare experimental ecological reserve operated by the University of Minnesota in cooperation with the Minnesota Academy of Sciences. CCNHA is located in Anoka and Isanti Counties north of Minneapolis/St. Paul. The site was established in 1940, was designated a National Natural Landmark by the National Park Service in 1975. In 1977 it was included as an Experimental Ecology Reserve in a proposed network, and in 1982 it was one of 11 sites in the U.S. selected by the National Science Foundation for funding of LTER.